Canister Purge Solenoid: Description and Operation

Fig. 3 Duty Cycle EVAP Purge Solenoid-Master Cylinder Removed:

PURPOSE
The duty cycle EVAP purge solenoid regulates the rate of vapor flow from the EVAP canister to the throttle body. The Powertrain Control Module (PCM) operates the solenoid.

OPERATION
During the cold start warm-up period and the hot start time delay, the PCM does not energize the solenoid. When de-energized, no vapors are purged.

When purging the PCM energizes and de-energizes the solenoid approximately 5 or 10 times per second, depending upon operating conditions. The PCM varies the vapor flow rate by changing solenoid pulse width. Pulse width is the amount of time the solenoid energizes.

The solenoid attaches to a bracket on the driver's side strut tower (Fig. 3). To operate correctly, the solenoid must be installed with the electrical connector on top.